Method of producing hydrocarbonoxygen compounds



J. c. WALKER 2,007,115

METHOD OF' PRODUCING HYDROCARBON OXYGEN COMPOUNDS` l July 2, 1935.

Filed Aug. 1o, 192'? 'Patented July 2, 1935l UNITED sTATEs PATENT oFFlcE DIETHOD OF PRODUCING HYDROCARBON- OXYGEN COIHPOUNDSl Application August 10, 1927, Serial No.'211,888

' 15 Claims.

This invention relates to the production of hydrocarbon-oxygen compounds by selective partial oxidation of one or more hydrocarbons present in a mixed body of hydrocarbons, and more particularly to a method of producing alcohols, aldehydes and other intermediate oxidation products by the selective partial oxidation of one or more vof the hydrocarbons such as ethane associated in a natural gas or other hydrocarbon mixture with less readily oxidizable hydrocarbons such' as methane.

It is well known that when a hydrocarbon body such as a natural gas is mixed with air or other oxygen supplying material in suitable proportions above the explosive range, a complete or substantially complete combustion of said hydrocarbon body can be made to take place. The principal products of such complete combustion are carbon dioxide and Water. It is also known that When a hydrocarbon body of the character above referred to is contacted with air or other oxygensupplying material in amounts insuicient to form an explosive mixture or to cause complete combustion, partial combustion reactions can be made to take place under suitable reaction conditions and in the presence of suitable catalysts, with the formation of small amounts of such intermediate hydrocarbon-oxygen compounds as alcohols, aldehydes, ketones and acids.

The primary object of the present invention is to provide a process for eiecting the selective partial oxidation of one or more hydrocarbons associated with other less readily oxidizable hydrocarbons in a hydrocarbon mixture.

A more specific object of the invention is to provide a process for producing acetaldehyde,

methanol, formaldehyde and other intermediate oxidation products by the selective partial oxidation of at least part of the hydrocarbon content of a body of natural gas or other hydrocarbon mixture containing both methane and hydrocarbons having a carbon content of C2 or higher.

.The method of the present invention constitutes an improvement on the methods of treating hydrocarbon gases described in my co-pending applications Ser. No. 165,656 filed February 3, 1927 and Ser. No. 192,077 filed May 17, 1927.

Another object of the present invention is to provid-e a process for effecting the selective partial oxidation of the heavier hydrocarbons associated with methane in a natural gas mixture with an oxygen-bearing gas under conditions which will yield valuable alcohol and aldehyde intermediate oxidation products and a gaseous residue which is substantially free of uncombined oxygen.

It has been found that a wide variation occurs in the heating value of the various types of natural gas which are now handled in the collection, transportation and distribution systems in the natural gas `producing areas. Gases ranging in caloric value from 650 to as high as 1800 B. t. u. per cubic foot or even higher arey thus handled. In order to provide their consumers with satisfactory service those collecting gas of Widely varying heating value recognize the value of distributing gas having the most desirable uniform heating value, flame temperature and other qualities.

Accordingly another object of the present invention is to provide a process for effecting the selective partial oxidation of ethane and higher paraflin hydrocarbons associated with methane in a natural gas under conditions which will yield valuable alcohols, aldehydes and other intermediate oxidation products and a gaseous residue of controlled uniform heating Value suitable for domestic and industrial fuel purposes.

With these and other objects and features in view the invention consists in the improved method for producing hydrocarbon-oxygen compounds by the selective partial oxidation of hydrocarbon mixtures hereinafter described and more particularly defined in the claims.

'Ihe various features of the invention are illustrated in the accompanying drawing in which:

Fig. l is a diagrammatic flow sheet of the method of the invention; and

Fig. 2 is a vertical cross-sectional View of one arrangement of reaction chamber suitable for use with the method of the invention.

The improved process may be carried out according to a plan illustrated diagrammatically -in the accompanying ow sheet (see Fig. l) substantially as follows:

The gas to be treated, for the purposes of ,this illustration considered as a natural gas of relatively high caloriflc value which contains methane and ethane, as well as small amounts of propane, butane, pentane, hexane and heptane, is drawn from a gas main I and passed through a dust separator l2 in Awhich any dust or foreign solid matter is removed. From the dust separator the gas is passed through a meter I4 in order to determine the rate of flow and the volume of gas to be treated. From the meter I4 the gas may be passed through a compressor I6 wherein it is compressed to a suitable, preferably relatively high, superatmospheric pressure. After being compressed the gas may be conducted through a gasoline absorbing apparatus 8 to remove any readily condensed and absorbed hydrocarbons, such as the natural gas gasoline hydrocarbons. If the gas is known to containl only very small amounts of the natural gas gasoline hydrocarbons, or if their rem-oval is not desired, it may be by-passed around the absorber I8 through a valved line 20. After passing the gasoline absorber and the by-pass 20 that portion of the gas which is to be treated is con-ducted into a manifold 22 through a valve 24. Any part of the gas which it is not desired to treat is passed on to the main line l0 through a valve 26. A suitable proportion'or all of the gas delivered to the manifold 22 is passed by a valved line 28 preferably into a preheater 30, illustrated in the drawing as of the interchanger type. From a heating element of the preheater or interchanger 30 the gas is delivered by a pipe 32 into the catalyst zone of an oxidation reaction chamber 42, the design of which will be hereinafter more fully described. Just before the gas to be treated is delivered to the reaction chamber 42 under a suitable superatmospheric pressure and with a suitable degree of preheat, a controlled relatively small proportion of air or other oxygen supplying fiuid under superatmospheric pressure is admixed therewith by jetting the air into the gas as it enters the base of the reaction chamber from a valve-controlled air supply line 34. Air is delivered to the line 34 from a manifold 36 which in turn receives a continuous supply of air delivered through a meter 38 from an air compressor 40. In the reaction chamber 42 the oxygen in the gas-air mixture is caused to selectively and completely unite with the ethane or other heavier hydrocarbon constituents of the natural gas by what may be termed a selective catalytic partial oxidation. 'I'he highly heated gaseous products of' the reaction leave the reaction chamber through a pipe 44 and are preferably passed immediately into heat interchanger 30 wherein rapid transfer -of a great part of their heat to fresh portions of natural gas to be treated is effected. From the heat transfer equipment the cool gaseous products of the reaction are passed by a line 46 in turn through a condenser 48 and a liquid absorber 50, wherein the intermediate oxidation products formed during the course of the treatment are separated and recovered, the .treated gaseous residue being finally passed into a manifold 52 which conducts it through a separator 54 and a valve 56 back to the gas distributing main I0. The apparatus is so arranged that the gaseous residue of the treatment above described may be recycled through the treating equipment just described in admixturewith fresh portions of gas by passing it through a valved connection 58 back into pipe 28, or else such gaseous residue may be passed by a valved connection 60 into a pipe line 28 leading to another set of apparatus units 42', 48 and 50 similar in arrangement to those just referred to, wherein the treatment is continued in another stage with the addition to the gas entering such stage of a relatively small proportion of oxygen-bearing gas. The hydrocarbon component of the reaction mixture thus formed is preheated in unit 30 and the mixture is contacted with a catalyst at a suitable reaction temperature in unit 42 and then treated in condensing and scrubbing equipment 48 and 50 respectively, for the removal of the condensible and absorbable intermediate oxidation products formed. The gaseous residue of the second stage of the treatment may be led olf through the connection 46' and manifold 52 to the gas distributing main I0, or it may be recycled through the apparatus of the second stage by passing it through a valved connection 58', or it may be given a third stage of oxidation treatment by passing it through a valved connection 60 and pipe line 28" into and through another set of apparatus units 32", 42", 48" and 50 in admixture with an additional small amount of oxygen supplying fluid. The gaseous residue from this third stage of the treatment may likewise be led off through manifold 52 or be recycled through a valved connection 58" or passed through a fourth stage of treatment in another similar set of apparatus units 32', 42"', 48' and 50 by conducting it through a connection E0" and a pipe 28', the final gaseous residue from the fourth stage than passing either back through a recycling connection 58"', or else through pipe 28" into manifold 52 and thence through separator 54 and valved connection 56 to the gas distributing main.

While the reaction chambers 42, 42', 42 and 42" may be of any approved construction commonly used for carrying out catalytic gas reactions, a preferred construction for such reaction chamber is shown in Fig. 2. Essentially this construction embodies a casing 63, preferably lined on its inner surface with a relatively thick layer 64 of heat insulating material. The inner chamber 66 of the reaction chamber is made substantially gas-tight, and an upright standppe 68 is mounted in substantially the central axis of chamber 66 for the purpose of conducting the mixture of gaseous hydrocarbons and oxygen-bearing gas introduced into the base thereof respectively through connections 32 and 34, to the top of the chamber. The hydrocarbon-oxygen mixture is passed from the upper portion of chamber 66 downwardly through an annular layer 10 of contact material maintained at a suitable reaction temperature, thence through grates I2 supporting the contact material and out through connection 44 to the cooling, condensing and scrubbing equipment.

While the process of the invention is not limited to or dependent on the use of any specific catalyst or contact substances, experience has shown that metallic or metal compound catalysts are apparently desirable. Very good results have been obtained with a catalyst comprising metallic platinum deposited on pumice material in the proportions of 10 grams of metal per cu. ft. of material. Other metallic or metal compound catalysts may be employed, deposited on other types of porous materials such as asbestos fibre or alundum. Excellent results have been obtained with many different metallic and metal compound contact bodies known to favor dehydration, dehydrogenation or oxidation reactions,

including palladium, chromium, manganese, iron,

copper, nickel, gold, silver and oxides of copper, manganese, iron, nickel, vanadium, chromium, molybdenum, cerium and other metals forming higher and lower oxides. Any mixture or alloy of the above named catalyst may likewise be used. The preferred catalyst or contact substance for use in accordance with the process of the present invention is one which will effectively promote the partial oxidation reactions yielding the primary or desired intermediate oxidation products at the lowest practicable temperatures, that is at a temperature such that the products of the reaction can be rapidly cooled below the critical temperature above which secondary reactions take place causing decomposition of the desired intermediate oxidation products.

The amount of air or other oxygen-supplying material that is added to the hydrocarbon mixture under treatment is regulated in accordance with the character of products desired and is also controlled by the reaction temperature which it is necessary to maintain in order to produce such products. Likewise the proportion of oxygensupplying material employed depends on several other variable factors, as for example the therto the time it enters the reaction chamber.

mal eiciency of the apparatus and the degree of preheat imparted to the reaction mixture prior In some cases the treatment may require the use of relatively large amounts of air or other oxygen-supplying material in order to maintain a suitable reaction temperature with a moderate heat gradient between the entering reaction constituents and the catalyst bed in apparatus of low thermal efciency, While exactly similar temperatures and heat gradients may be maintained in thermally eiiicient apparatus using a very much smaller proportion of oxygen-supplying material in the reaction mixture. Assuming that a definite mixture of natural gas and air is under treatment, the temperature of the reaction chamber may be regulated not only in accordance with the proportion of air employed but also by the amount of preheat imparted to the reaction mixture prior to its admission to the reaction chamber. Referring to the drawing this regulation of preheat may be accomplished by proper regulation of the Valves in conduits 62, 62', 62 and 62 whereby a suitable proportion of the hydrocarbon mixture under treatment may be by-passed around the preheaters or interchangers 30, 30', 30" and' 30" while another part is passed through the interchangers, the proportions of gas passed through and by-passed around the interchanger determining the degree of preheat imparted to the gas-air mixture entering the reaction chamber. The construction of the catalyst chamber shown in Fig. 2 is such that considerable heat interchange takes place therein between the gas-air mixture entering through standpipe 68 and the catalystbody l0 and the products of the reaction passing downwardly through the catalyst body toward the exit pipe 44. vCooling of the catalyst bed 10 by heat interchange with the hydrocarbon-air mixture on its way to the catalyst zone apparently plays an important part in the process in in- Suring a moderate temperature gradient between the gases entering the reaction zone and the point of optimum maximum reaction temperature within the catalyst bed. Likewise rapid cooling of the products of the reaction by heat interchange with the hydrocarbon-air mixture entering the reactionchamber plays an important part in providing an increasing temperature gradient between the point of maximum reaction temperature in the catalyst bed and the gas leaving the reaction zone, thereby retarding the thermal decomposition of the intermediate oxidation products formed.

The air or other oxygen-supplying gas which is introduced into the reaction chamber through the connections'34, 34', 34" and 34 is preferably placed under a superatmospheric pressure slightly above that maintained on the hydrocarbon mixture introduced through conduits 32, 32', 32" and 32" in order to prevent flow of hydrocarbons back into the air-supply mains and in order to insure a thorough mixing of the air and gas, as by jetting the air into the gas at the base of standpipe 68.

The reaction in chamber 42 between the oxygen and the ethane or other readily oxidizable hydrocarbon in the reaction mixture proceeds with great rapidity, and if relatively large proportions of air or other oxygen-supplying gas are employed in the reaction mixture the temperature in the reaction zone will tend to rise too high. It has been found that the best yields of alcohol and aldehyde are obtained from the selective partial oxidation of the ethane content of a natural gas consisting chiey of ethane and methane in accordance with the present process when the reaction temperature in the catalyst bed is maintained substantially uniformly in the neighborhood of G-900 F., preferably about 850 F., under the preferred conditions of pressure, proportions of reaction constituents, time of contact of said constituents with the catalyst and the like, hereinafter discussed. It has also been observed that as the reaction temperature rises much `above 900 F., for example to 1000 F., or above, the yield of alcohols and aldehydes becomes 'decidedly'pooren entirely disappearing at higher temperatures with the formation of carbon monoxide, carbon dioxide and hydrogen. It has been particularly noticed that the yield of methanol becomes decidedly and markedly poorer whenever the reaction temperature is allowed to Vary much more than 200-300 F. from the desired temperature of about 850 F.

In cases where the desired character and yield of intermediate oxidation products can only be obtained by addition to the hydrocarbon mixture under treatment of a greater volume of oxygensupplying gas than can be satisfactorily used without exceeding the maximum desired reaction temperature limits at which the best yields are obtainable, the best method for controlling the temperatures to be maintained in the reaction zone has been found to be the use of a multiple -stage oxidation treatment of the gas such as that already described. The number of stages necessary for suitably treating the gas is determined by the maximum temperature desired in each stage and by the total volume of air or other oxygen-supplying gas which it is necessary to add in order to produce a suitable yield of intermediate oxidation products. As. already in-dicated the hot gaseous products of each stage of the treatment are preferably cooled and the liquid condensate is preferably trapped oi therefrom before preparing a new reaction mixture of the gaseous residue and an oxygen supplying material for treatment in the next stage. The

same catalyst may be used in all stages, or different catalysts may be used in any of the stages, as desired. Likewise the conditions of operation in each of the several stages may be varied for the purpose of producing relatively large proportions of one type of hydrocarbon intermediate oxidation products, as for example methanol or other alcohol, as the principal product in one stage, while later producing another and entirely diiTerent product, such as formaldehyde for example, in another stage. Moreover, such conditions of operation may be readily controlled so as to selectively oxidize one or more constituents of the hydrocarbon mixture under treatment, such as ethane for example, in one stage, while oxidizing another entirely different component of the mixture, such as methane, in another stage. As shown in the drawing the apparatus is preferably so arranged that the treatment can be completed in one stage if desired, each unit assembly of heat interchanger, condenser and absorber being arranged so that it can be operated in parallel with the other unit assemblies in the treatment of separate portions of hydrocarbonmixture taken from the main supply manifold 22, with separate portions of air or other oxygen supplying gas taken from the supply manifold 36 leading from the compressor 40. A single stage treatment is normally used in cases where it is desired to treat a natural gas, for example, to produce a limited Cil volume of alcohol, aldehyde, ketone or acid intermediate oxidation products, together with a gaseous fuel residue having a controlled uniform calorifc value that is substantially free of uncombined oxygen.

As a specific example of the present process one method of treating a natural gas comprising about 1A part ethane and 3/4 parts methane, together with small amounts of impurities, including some uncombined oxygen, will now be described. A body of the above gas is placed under a superatmospheric pressure-of about 300 lbs. per sq. in. and is then preheated to a temperature of about 750 F. Air under a slightly higher pressure is added to the gas in the proportions of about 10% by volume of the gas, and the mixture thus formed is introduced into a reaction chamber of the general type and arrangement illustrated in the drawing, the gas-air mixture being rst passed in indirect heat interchange relation with a catalyst bed of platinized pumice maintained at a temperature of about 850 F. and thence through the bed at a rate such that each unit volume of the mixture is in contact with the catalyst for a period not substantially exceeding four seconds. The hot products of the partial oxidation reactions' which take place in the catalyst zone are product thus separated from the gaseous residue of the treatment is found on analysis to consist partly of Water and partly of a mixture of intermediate oxidation products. On analysis the mixture of intermediate oxidation products or substantially non-aqueous liquid components of the mixture formed are found to comprise by volume approximately 2 to 4% acetaldehyde and higher aldehydes, 60% methanol, 25% of 40% formaldehyde, and a residue apparently containing chiefly carbohydrates and resinied aldehydes. The gaseous residue of the above treatment consists of about 70% methane, 17% ethane, 10% nitrogen and small amounts of carbon oxides, hydrogen and unsaturated hydrocarbon illuminants, largely olenes. Normally no uncombined oxygen will be present in the gaseous residue. It will be observed that as a result of the above treatment most of the methane content of the original gas has passed through the reaction chamber unchanged, Whereas the proportionate concentration of ethane in the gas has decreased considerably, having been converted during the course of the treatment into aldehydes, methanol and other intermediate oxidation products formed.

A natural gas containing substantial proportions of propane, butane, or other higher paraflin hydrocarbons, or a mixture of such hydrocarbons together with methane or other relatively nonoxidizable hydrocarbon may be used in place of a gas comprising ethane and methane with ,substantially similar results, although the partial oxidation products formed will carry a higher proportion of hydrocarbon-oxygen compounds having a higher molecular weight than the acetaldehyde and other partial oxidation products formed in the specic example above referred to. Because of the fact that the members of the paraflln group of hydrocarbons are in general more readily oxidized the higher their molecular weight, it is possible, as shown in the specific example given, to so control the variable factors or conditions of pressure, temperature, proportions of reaction constituents, catalysts, degrees of preheat and time of contact of the reaction mixture with the catalyst, that only the higher members of the series of hydrocarbons present in a body of natural gas or other hydrocarbon mixture Will respond to the partial oxidation treatment, the lower less readily oxidizable members of the series, such as methane, passing through the reaction chamber substantially unchanged. One distinctly advantageous feature of the present process is the admixture with the hydrocarbon which is to be treated of a less readily oxidizable hydrocarbon in relatively large amounts, thereby relying on the selective attraction of the more readily oxidizable hydrocarbons in the mixture for the oxidizing medium and proting by the presence of the less readily oxidizable hydrocarbons in the reaction mixture for promoting a more thorough contact and distribution of the constituents of the selective oxidation reaction over the catalyst surface, for creatingv partial pressure enects, and for retarding decomposition of the intermediate oxidation products formed. In treating ethane, for example, it is advantageous to admix therewith, prior to the treatment, large amounts of methane, preferably in the proportions of three or four parts of methane or more to one of ethane, as in the specific example above discussed.

Relatively large commercial yields of methanol and aldehyde products have been obtained by treating bodies of natural gas similar to that referred to in the above specic example at pressures ranging from 100 lbs. or 150 to 300 lbs. per sq. in. or above. It has been found that the best yields of alcohol and aldehyde products are obtained when the hydrocarbon mixture under treatment is first preheated to Within 50-200 F. of the desired reaction temperature, after which just suicient air or its equivalent is added to the thus preheated hydrocarbon mixture so that the optimum temperature at .which the best yields of alcohol and aldehyde products are formed is just maintained by the heat of the reaction set up in the reaction chamber, and is never substantially exceeded. The amount of air which it is thus necessary to add is seldom more than 50% by volume of the hydrocarbon mixture, and normally ranges from 4% to 15% or 20% by volume of the hydrocarbon, the amount of air used within these limits being determined by the proportion of reactive hydrocarbon component, by the degree of preheat imparted to the gas, and by the efciency of heat interchange and heat insulation of the apparatus.

In order to prevent decomposition of the methanol and aldehyde intermediate oxidation products formed, it is distinctly advantageous to so control the character and degree of preheat imparted to the reaction mixture that its temperature is carried upwardly gently and uniformly to the desired reaction temperature without the occurrence of local overheating. The formation of intermediate oxidation products by the selective partial oxidation process of the present invention involves exothermic reactions and a decrease in volume of reaction products over the corresponding volume of constituents taking part in the reaction. Similarly decomposition of the reaction products formed involves an increase in volume of products. Most of the intermediate oxidation products are extremely unstable, and by maintaining uniform controlled superatmospheric pressure conditions throughout all parts of the apparatus thosev reactions in which products are formed having a lesser volume than that of the reacting constituents, are promoted and allowed to take place under the optimum pressure conditions producing the highest yields of such oxidation products, while at the same time the decomposition of such products into other compounds of greater volume is prevented or greatly retarded. Similarly by controlling the temperature of the reaction and the character and degree of prelieat imparted to the reactive and nonreactive constituents entering the reaction zone, as Well as the degree and character of cooling of the products formed', as by eecting a rapid heat interchange between the products of the reaction, the 'catalyst bed and the hydrocarbons on their way to the reaction zone, suitable moderate temperature gradients can be maintained between the gases entering and leaving the point of optimum temperature in the catalyst bed, thereby producing suitable yield of intermediate oxidation products and protecting such products from thermal decomposition.

While it is desirable to carry on the reactions of the present process in such a way that the reaction constituents are contacted for only a very brief interval with the point of highest temperature in the reaction zone, it has been found that by arranging the reaction chamber in such a way that an efficient heat interchange can take place between the catalyst or other contact body and the constituents and/or products of the reaction, the depth of the contact material within the reaction chamber can be varied so that the reaction mixture is in contact with the catalyst for periods ranging from less than 1A; seconds to six seconds or more without seriously affecting the yield of desired intermediate oxidation products formed, other reaction conditions remaining unchanged. The process of the invention is not limited to the use of any particular type or arrangement of apparatus units, andv it is believed that most of the apparatus equipment for eiecting the necessary preheating, reaction contact and cooling and scrubbing of the reaction products, as wellas that necessary for initiating and maintaining the proper temperatures in the reaction zone, is available in many suitable forms.

The chief advantage resulting from the use of a catalyst is apparently that by such use the desired reactions can be caused to proceed to completion at relatively much lower temperatures than would be necessary were no catalyst employed.

While in the foregoing description natural gas hydrocarbons of the parafn group have been chiefly referred to, it is to be understood that the invention is not limited to the tratment of natural gas or paraffin hydrocarbon mixtures, but on the contrary the principles thereof may be applied to the treatment of other hydrocarbon mixtures such, for example, as the gases derived from the distillation of coal or the olefine and other hydrocarbon gases or vapors formed by the thermal decomposition of petroleum and oil shale. Moreover, while the process of the invention relates chiey to the selective oxidation of one or more of the members of a hydrocarbon mixture to form alcohol and aldehyde intermediate oxidation products, it will be understood that by suitably varying the factors controlling the oxidation reactions other valuable intermediate oxidation products may be obtained. Thus in the specific example given above, the yield of aldehydes may be considerably increased at the expense of a decrease in the proportionate yield of methanol by varying some of the reaction conditions, particularly those of pressure and temperature.

Pure oxygen, ozone, carbon oxides or other materials capable of supplying oxygen under the conditions of pressure, temperature and the like maintained within the reaction zone, may be used in place of air as the oxidizing agent. Likewise materials other than the nitrogen of the air may be used to advantage as inert diluents for the oxidizing agent. Likewise, other hydrocarbons capable of resisting a partial oxidation treatment under the conditions of temperature, pressure and the like maintained in the reaction zone of the treating equipment may be employed in place of the methane of the specic example given as a diluent or non-reactive buier agent for the hydrocarbon which it is desired to treat.

In the foregoing discussion the invention has been described as based upon the theory that readily oxidizable hydrocarbons, and particularly members of the paraffin series of hydrocarbons having a carbon content of C2 or higher, can be selectively converted by partial oxidation reactions into alcohols, aldehydes and other intermediate oxidation products while associated with relatively large proportions of less readily oxidizable or buffer hydrocarbons such as methane. It is to be understood however that in its broadest scope the invention is not based on any definite theory as to the character of the reactions taking place resulting in the production of intermediate oxidation products together with a gaseous residue which is relatively much leaner with respect to its content of one or more of the hydrocarbon components of the original mixture treated by the partial oxidation treatment of a. mixture of hydrocarbons of the class described.

The invention having been thus described, what is claimed as new is:

1. In the manufacture of partial oxidation products of hydrocarbons, the process which comprises heating an intimate mixture of two fluid aliphatic hydrocarbons together with 0.8%-l0% by volume of said mixture of oxygen, to a temperature of 550 F.l000 F. carrying out the reaction in the vapor phase under a high superatmospheric pressure, and separating the intermediate oxidation products formed from the unreacted residue.

2. The process which comprises heating an intimate mixture of .a plurality of normally gaseous aliphatic hydrocarbons, together with from 0.8 %10% by volume of said mixture of oxygen, to a temperature of 550 F. to 1000 F. under a .pressure in excess of l00 lbs. per square inch, cooling the products of the reaction thus set up, and separating condensible liquid products from the residue of the treatment.

3. The process -of selectively converting the ethane and heavier aliphatic hydrocarbon components of natural gas into an intermediate oxidation product comprising treating said gas to a selective partial oxidation, at a temperature in the range 550 F. to 1000 F., and under a high pressure above 100 pounds per square inch, with an oxygen-supplying gas admixed therewith in the proportions of 0.8% to 10% by volume of free oxygen equivalent for every volume of gas under treatment.

4. A method of selectively converting the ethane and heavier hydrocarbon components of a. fluid hydrocarbon mixture containing methane into an intermediate oxidation product, comprising subjecting said hydrocarbon mixture in the vapor phase to a selective vpartial oxidation treatment with 0.8%-10% its volume of oxygen at a reaction temperature in the range 550 F.1000 F. under a pressure above 100 pounds per square inch, cooling the products of the reaction and separating the intermediate oxidation product formed from the residue of the treatment, successively treating such hydrocarbon residue in a similar manner, and employing Just sulcient oxygen supplying material in each stage of the treatment to maintain the reaction temperature for that stage.

5. The method of producing an intermediate hydrocarbon oxidation product which comprises placing natural gas under a superatmospheric pressure above 100 lbs. per square inch, preheating said gas to a temperature approaching within 200 F. below the reaction temperature, admixing an oxygen-supplying gas therewith in the proportions of 0.8%-10% by volume of free oxygen equivalent per volume of gas under treatment, contacting said mixture with a catalyst for a period of between 1A and 4 seconds at a temperature of about 550 F.1000 F., rapidly cooling the products of the reaction, and separating the intermediate oxidation product formed from the gaseous residue.

6. A process comprising treating a iluid hydrocarbon mixture including an aliphatic hydrocarbon containing more than 1 carbon atom to the molecule, to partial oxidation with an oxygensupplying material at a reaction temperature of 550F.-1000F. under a pressure above 100 pounds per square inch, characterized by the fact that the oxygen-supplying material is used in the proportions of between 0.8% and 10% by volume of free oxygen for each volume of hydrocarbon.

7. A process according to claim 6, in which the reaction is carried out under a pressure above 300 pounds per square inch and at a reaction temperature below 900 F.

8. The method of producing a liquid aliphatic hydrocarbon oxygen compound which comprises subjecting a uid aliphatic hydrocarbon containing more than 1 carbon atom to the molecule and while admixed with an inert gas, to partial oxidation reaction with 0.8% to 10% by volume of the hydrocarbon-inert gas mixture of free oxygen, under pressures above 100 pounds per square inch, cooling the gaseous products of the reaction and separating hydrocarbon oxygen compounds formed from the cooled gaseous residue.

9. The process for the manufacture of intermediate hydrocarbon oxidation products which comprises subjecting a uid aliphatic hydrocarbon mixture to a partial oxidation with between 0.8% and 2.5% of its volume of oxygen to a temperature in the range 550F.-1000 F. and under a pressure exceeding 100 pounds per square inch.

10. The process for the manufacture of intermediate hydrocarbon oxidation products which comprises subjecting a iiuid aliphatic hydrocarbon mixture to a partial oxidation with between 4% and 20% of its volume of air to a temperature in the range 550 F.-1000 F. and under a pressure exceeding 100 pounds per square inch.

11. The method of converting a fluid aliphatic hydrocarbon containing more than one carbon atom in its molecule into an intermediate oxidation product, which comprises placing a mixture of said hydrocarbon and a substantially nonreactive hydrocarbon diluent under a superatmospheric pressure above 100 pounds per square inch, preheating said hydrocarbon mixture, admixing air with the preheated hydrocarbons in the proportions of from 4 to 50% by volume of air per volume of hydrocarbon, passing the airhydrocarbon mixture rapidly through a high temperature reaction zone and subjecting the mixture in said zone to a temperature oi' 550 F. to 1000 F. for a period o! from 1/4 to 4 seconds, rapidly cooling the products of the reaction, and separating the intermediate oxidation products formed from the gaseous residue.

12. The process oi' selectively converting the ethane and higher fluid hydrocarbon components o! an aliphatic hydrocarbon mixture containing methane into intermediate oxidation products, which comprises reacting said hydrocarbon mixture with less than 116th by volume of said mixture of free oxygen at a temperature in the range of 550 F. to 1000 F., carrying out the reaction in the vapor phase under a pressure above 100 pounds per square inch, rapidly cooling the products of the reaction, and separating intermediate oxidationl products formed from unreacted residue.

13. The process for converting 'ethane and other fluid aliphatic hydrocarbons containing at least two carbon atoms in the molecule into intermediate oxidation products, which comprises partially oxidizing said hydrocarbon with between .8% and 10% its volume of oxygen at a temperature of 550 F. to 1000 F., and under a pressure oi above 100 pounds per square inch, maintaining the reaction mixture at reaction temperature for a brief period of from 1/4 to 4 seconds, and rapidly cooling the products of the reaction.

14. The process of selectively converting the ethane and heavier fluid aliphatic hydrocarbon components of a gas containing methane, into intermediate oxidation products,. which comprises placing said gas under a pressure of at least 100 pounds per square inch, preheating the gas and thereafter admixing air under pressure therewith in proportions of 4% to 50% by volume of air for each volume of gas, conducting said air-gas mixture through a rreaction zone at a rate such that the mixture is subjected to reaction temperature in the range of 550 F. to 1000 F. for a period of from lAth to 4 seconds, and rapidly cooling the products of reaction to separate partial oxidation products formed from the gaseous residue.

15. The method of converting ethane and heavier fluid aliphatic hydrocarbon components of a nuid hydrocarbon mixture into intermediate oxidation products and an oxygen-free gaseous residue, which comprises placing said hydrocarbon under a superatmospheric pressure above 100 pounds per square inch, preheating said hydrocarbon and mixing oxygen under pressure therewith in the proportions of between .8 to 10% by volume of oxygen per volume of hydrocarbon, reacting the hydrocarbon and oxygen components of the mixture for a period of from 1A to 4 seconds at a temperature of 550 F. to 1000 F., rapidly cooling the products of the reaction, and separately recovering liquid oxidation products and an oxygen-free gaseous residue.

JOHN CHARLES WALKER. 

